2009 is the International Year of Astronomy. And every month this year we’ll be showcasing a great celestial view. This month it’s the Andromeda Galaxy!

Credit: The Andromeda galaxy. Andromeda is the nearest major galaxy to our own Milky Way Galaxy. Credit & Copyright: Robert Gendler/NASA

When you look up at the October sky you’ll easily see solar system objects like Jupiter and the moon. You can also see stars, clumps and knots of nebulosity in our Milky Way Galaxy.

But did you know you can actually see another galaxy with your own eyes, even without a telescope? The Andromeda Galaxy is the most distant easily visible object in the sky, and it’s also the largest and closest spiral galaxy that we can see.

It’s visible even under moderate light polluted skies as a misty patch. Through binoculars and telescopes more and more detail is revealed to the observer.

Astronomers have observed the Andromeda galaxy for over a thousand years. Persian astronomer Al-Sufi was the first to record and sketch his observations of what he called “the little cloud”. In 964 he published this observation and many others in his “Book of Fixed Stars”.

Since the 16th century many astronomers rediscovered the Andromeda Galaxy unaware of the earlier sightings. Simon Marius first viewed the galaxy through a telescope in 1612.

It is also known as M-31 on Charles Messier’s list of objects, although he was aware of some earlier sightings.

In 1887 the first photograph revealed the spiral structure of the Andromeda Galaxy, which was then known as a nebula. And in the early 20th century Edwin Hubble’s study of Andromeda nebula proved the nebula was not just a star cluster in our own Milky Way, but a separate galaxy.

In addition to the Andromeda Galaxy, you can still catch a great view of our Milky Way galaxy this month. Both are nearly overhead, but while distant Andromeda is seen as a fuzzy oval in the constellation Andromeda, the Milky Way spans the sky from east to overhead to the west. It’s a gorgeous site from a dark sky again this month.

Back to our solar system, Jupiter reigns as king of the planets in the western sky and Mars will rise before midnight by the end of the month, making it a late night pumpkin-colored treat on Halloween.